To be responsive to customers' needs, integrated circuit manufacturers strive to have a wide variety of integrated circuit types to satisfy their customers' needs. Many of these different types are minor modifications of chips that are fundamentally similar. An example of that is the different mode types of dynamic random access memories (DRAMS) which are provided. Some examples of different modes of operations are providing 1-bit output data, 4-bit output data, 8-bit output data, static column and page modes. Each of these modes may help the performance of a system in its own particular way. However, fundamentally each provides the function of storing a set amount of data.
In order to expedite design time and minimize manufacturing costs, integrated circuit manufacturers have designed several mode types into a fundamental design. Some of these multiple design integrated circuits are programmed by providing different metal configurations in the last metalization step. The photomasking for this metalization step may be easily changed in the production line or partially finished integrated circuits may be stored in order to quickly perform the final masking step and quickly provide the desired integrated circuit to the customer. This has been an effective strategy in the industry, but still requires changes to be made in the relatively complicated metalization masking step of the integrated circuit fabrication process. In addition, until the final protective layers are placed over the top of the integrated circuit, the integrated circuit remains very vulnerable to contamination.
Another method devised for providing multiple mode functions is the provision of a pin of the integrated circuit to alter the mode of the integrated circuit depending on the signal provided to that pin. Thus a logical 1 or 0 placed on the mode pin or pins effects the appropriate functional operation. This concept has been carried one step further by obtaining the signal inside of the integrated circuit package by bonding the mode selection bonding pads directly to the appropriate one of a positive voltage supply for logical 1 or ground for a logical 0. This bond programability provides a better solution than changing the metalization by moving the programming step downstream from the integrated circuit manufacturing process to the packaging step. However, each bond pad must be properly connected providing undue complexity in the packaging stage.